U.S. patent application number 16/242031 was filed with the patent office on 2020-01-23 for production method of ceramic matrix composite.
This patent application is currently assigned to IHI Corporation. The applicant listed for this patent is IHI Corporation. Invention is credited to Ryoji Kakiuchi, Shingo KANAZAWA, Yousuke Mizokami, Yuuya Nagami, Takeshi Nakamura, Akihiro SATO.
Application Number | 20200024199 16/242031 |
Document ID | / |
Family ID | 61561533 |
Filed Date | 2020-01-23 |
United States Patent
Application |
20200024199 |
Kind Code |
A1 |
KANAZAWA; Shingo ; et
al. |
January 23, 2020 |
PRODUCTION METHOD OF CERAMIC MATRIX COMPOSITE
Abstract
A production method of a ceramic matrix composite is consisted
of: forming a ceramic compact including one or more of a
reinforcement fiber and a powder, each including SiC; attaching an
ingot of a ternary or more multicomponent Si alloy including Y onto
the ceramic compact; and infiltrating the alloy into the ceramic
compact by heating up to a temperature at which the alloy
melts.
Inventors: |
KANAZAWA; Shingo; (Tokyo,
JP) ; SATO; Akihiro; (Tokyo, JP) ; Mizokami;
Yousuke; (Tokyo, JP) ; Nakamura; Takeshi;
(Tokyo, JP) ; Kakiuchi; Ryoji; (Tokyo, JP)
; Nagami; Yuuya; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IHI Corporation |
Koto-ku |
|
JP |
|
|
Assignee: |
IHI Corporation
Koto-ku
JP
|
Family ID: |
61561533 |
Appl. No.: |
16/242031 |
Filed: |
January 8, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2017/019862 |
May 29, 2017 |
|
|
|
16242031 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C04B 35/565 20130101;
C04B 41/88 20130101; C04B 41/85 20130101; C04B 35/573 20130101;
C04B 35/62868 20130101; C04B 2235/614 20130101; C22C 1/10 20130101;
C04B 2235/422 20130101; C04B 2235/404 20130101; C04B 35/62873
20130101; C04B 2235/40 20130101; C04B 2235/5244 20130101; C04B
2235/616 20130101; C04B 35/806 20130101; C04B 2235/3826
20130101 |
International
Class: |
C04B 35/80 20060101
C04B035/80; C04B 35/565 20060101 C04B035/565 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 6, 2016 |
JP |
2016-173455 |
Claims
1. A production method of a ceramic matrix composite, the method
comprising: forming a ceramic compact comprising at least one of a
reinforcement fiber and a powder, each comprising SiC; attaching an
ingot of a ternary or more multicomponent Si alloy comprising Y
onto the ceramic compact; and infiltrating the alloy into the
ceramic compact by heating up to a temperature at which the alloy
melts.
2. The production method of claim 1, wherein the Si alloy
comprises: 2% or more and 30% or less Y; and 2% or more and 15% or
less Ti or Hf.
3. The production method of claim 1, wherein the Si alloy consists
essentially of: 2% or more and 18% or less Y; 2% or more and 15% or
less Ti or Hf.
4. The production method of claim 1, wherein a content of Y in the
Si alloy is from 2% to 6%.
5. The production method of claim 1, wherein a content of Ti in the
Si alloy is from 6% to 10%.
6. The production method of claim 1, further comprising: prior to
the step of attaching the ingot, infiltrating a powder of any one
or more of SiC and C into the ceramic compact.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation Application of PCT
International Application No. PCT/JP2017/019862 (filed May 29,
2017), which is in turn based upon and claims the benefit of
priority from Japanese Patent Application No. 2016-173455 (filed
Sep. 6, 2016), the entire contents of which are incorporated herein
by reference.
BACKGROUND
Technical Field
[0002] The disclosure herein relates to a production method for a
ceramic matrix composite applied to devices requiring
high-temperature strength, such as aircraft jet engines.
Related Art
[0003] Ceramics have excellent heat resistance but at the same time
many of them have a drawback of brittleness. Many attempts to
combine fibers of a ceramic with a matrix of another ceramic or a
metal have been studied in order to overcome the brittleness.
[0004] As a process for combining, proposed are methods of chemical
vapor infiltration (CVI), liquid phase infiltration (such as
polymer infiltration pyrolysis (PIP)), solid phase infiltration
(SPI), and molten metal infiltration (MI) for example. According to
the MI method for example, an ingot of a metal from which the
matrix is originated is attached onto a fabric of fibers such as
SiC and the combination is melted, thereby combining the matrix
with this reinforcing fibers.
[0005] Combined arts in which some of these methods are combined
have been proposed. Japanese Patent Application Laid-open No.
2013-147366 discloses a related art.
SUMMARY
[0006] The MI method, as inherently reinforcement fibers are
exposed to high temperatures in this method, sometimes causes the
reinforcement fibers to deteriorate to an unignorable extent.
Considering that silicon (Si) is to be melted and infiltrated, the
reinforcement fibers should be exposed to high temperatures at
least higher than the melting point for the purpose of melting and
infiltration, while the melting point of Si is 1414 degrees C. In
addition, such high temperatures would put a considerable load on a
reaction furnace.
[0007] The production method disclosed below has been created in
the aforementioned problems. According to an aspect, a production
method of a ceramic matrix composite is consisted of: forming a
ceramic compact including one or more of a reinforcement fiber and
a powder, each including SiC; attaching an ingot of a ternary or
more multicomponent Si alloy including Y onto the ceramic compact;
and infiltrating the alloy into the ceramic compact by heating up
to a temperature at which the alloy melts.
[0008] Preferably, the Si alloy includes: 2 at % or more and 30 at
% or less Y; and 2 at % or more and 15 at % or less Ti or Hf.
Alternatively, the Si alloy consists of: 2 at % or more and 30 at %
or less Y; 2 at % or more and 15 at % or less Ti or Hf; and
unavoidable impurities and a balance Si. Alternatively preferably,
in the Si alloy, the content of Y is in a range of from 2 at % to 6
at %. Still preferably, in the Si alloy, the content of Ti is in a
range of from 6 at % to 10 at %. More preferably, the production
method further includes, prior to the step of attaching the ingot,
infiltrating a powder of any one or more of SiC and C into the
ceramic compact.
Advantageous Effects
[0009] Deterioration of the reinforcement fibers by high
temperatures in the step of melting could be prevented.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a flowchart generally describing a production
method of a ceramic matrix composite according to an
embodiment.
[0011] FIG. 2A is a sectional view schematically depicting a state
where an ingot is attached onto a compact in a step of melting.
[0012] FIG. 2B is a sectional view schematically depicting a state
where the ingot is infiltrated into the compact in the step of
melting.
[0013] FIG. 2C is a sectional view schematically depicting a state
where the ingot finishes being infiltrated into the compact in the
step of melting.
[0014] FIG. 3 is a graph showing an influence of a composition of
the ingot on a ratio of infiltration.
[0015] FIG. 4 is a graph showing an influence of an yttrium content
in the ingot on oxidation resistance.
[0016] FIG. 5 is a graph showing an influence of a titanium content
in the ingot on the Young's modulus.
DESCRIPTION OF EMBODIMENTS
[0017] Exemplary embodiments will be described hereinafter with
reference to the appended drawings.
[0018] Preferably applicable uses of ceramic matrix composites
according to the embodiments are any machinery components exposed
to high-temperature environments, such as components used for
aeronautic jet engines, and its examples are turbine blades,
combustors, after-burners and such. Of course any other uses are
possible.
[0019] A ceramic matrix composite according to an embodiment is
produced generally by forming a ceramic compact consisting of one
or more of reinforcement fibers and powder of a ceramic such as
silicon carbide (SiC) and melting and infiltrating a silicon (Si)
alloy of a ternary or more multicomponent Si alloy into the ceramic
compact. The matrix, in which the Si alloy is infiltrated, combines
the SiC fabric and/or the powder together, thereby forming the
ceramic matrix composite. Further, to form the matrix, any one or
more of chemical vapor infiltration (CVI), liquid phase
infiltration (such as polymer infiltration pyrolysis (PIP)) and
solid phase infiltration (SPI) can be combined thereto.
[0020] A production method of the ceramic matrix composite will be
described hereafter mainly with reference to FIG. 1. First, a
ceramic compact is formed in a predetermined shape that is
determined in accordance with its use (Step S1). The reinforcement
fibers of the ceramic may be left as a bundle of the fibers but may
be in advance woven into a fabric, and further may be in advance
subject to infiltration of the ceramic powder. An example for the
ceramic is SiC but carbon (C), boron nitride (BN) or any other
proper ceramic is still applicable and any mixture thereof may be
also applied thereto. The reinforcement fibers and the powder may
be of a common ceramic or alternatively of distinct ceramics
respectively. Further the fabric may be either two-dimensionally
woven or three-dimensionally woven.
[0021] The reinforcement fibers may be processed with coating. C
and BN can be exemplified as the coating layer but are not
limiting. Any publicly known production method such as vapor
deposition methods and dip methods may be applicable to its
production. Further the coating may be deposited before or after
the step of forming. The interface coating prevents crack
propagation from the matrix to the fibers and increases
toughness.
[0022] In a case where the ceramic compact is produced generally
from ceramic powder, the powder may be in advance press-formed and
pre-sintered.
[0023] Regardless of whether the ceramic compact is formed of the
reinforcement fibers including the ceramic powder or generally of
the ceramic powder, it may contain a second ceramic powder
distinctive therefrom. It may for instance contain C powder
further. The C powder can react with the molten Si alloy to produce
SiC, which contributes improvement of strength of the ceramic
matrix composite.
[0024] In parallel with formation of the ceramic compact, an ingot
to be melted and infiltrated therein is produced (Step S3). The
alloy is for instance a ternary Si alloy such as an yttrium
(Y)-titanium (Ti)-Si alloy. As described already, a three or more
multi component Si alloy is instead applicable.
[0025] In these Si alloys, alloying with solutes causes
melting-point depression and therefore the melting points are lower
than that of pure Si (1414 degrees C.). On the other hand, while
many reinforcement fibers will rapidly deteriorate at 1400 degrees
or higher, this deterioration is sensitive to temperature because
it is based on chemical reactions that conform the Arrhenius
equation. Slight temperature depression around 1400 degrees C. will
prominently decelerate the deterioration speed. Specifically, the
melting-point depression by alloying is available for suppressing
deterioration of the reinforcement fibers.
[0026] As compared with addition of a single element to Si, adding
plural elements in combination is more preferable. In a case of
adding Ti alone for instance, adding 15 at % Ti to Si depresses the
melting point just only down to 1330 degrees C. This composition is
a so-called eutectic composition in the Si--Ti system and 1330
degrees C. is a so-called eutectic point as the lowest melting
point in this system. If Si is, in the process of infiltration,
exhausted in the carbonizing reaction and the composition in the
molten metal is deviated from the eutectic composition toward the
Ti-rich side, the melting point increases and then progress of
infiltration will be barred anymore. When Y in combination with Ti
is added at 2 at % for instance, this phenomenon is effectively
prevented and sufficient infiltration can be expected. As excessive
addition of Y rather increases the melting point, it is preferably
30 at % or less, or more preferably 18 at %, which is the eutectic
composition, or less.
[0027] On the other hand, according to studies by the present
inventors, addition of Y seems disadvantageous in light of
oxidation resistance of the ceramic matrix composite, while
addition of Ti or Hf seems preferable in improvement of the
oxidation resistance. Thus it is rational to add a relatively small
amount of Y along with Ti or Hf in light of improvement of both the
infiltration ability and the oxidation resistance. As described
above, to the ingot preferably applicable is a ternary or more
multicomponent Si alloy including Y, such as a multicomponent Si
alloy including Y and Ti for instance.
[0028] More specifically, in the step S3, an ingot preferably of a
ternary or more multicomponent Si alloy is produced. The ingot is
formed in a proper shape and dimensions so designed with a shape of
the ceramic compact to be attached in mind. Referring to FIG. 2A,
the produced ingot 3 is attached to the ceramic compact 1 and
inserted into a reaction furnace. Preferably the furnace is
evacuated down to a vacuum or purged by introduced inert gas such
as argon.
[0029] Referring again to FIG. 1, to melt and infiltrate the ingot
3 into the ceramic compact 1 (step S5), the ceramic compact 1 and
the ingot 3 is heated in the furnace.
[0030] A temperature profile in the step of heating can be
exemplified by the following description for instance. A rate of
temperature increase is 10 degrees C./min for instance while it may
be properly selected. In the process of temperature increase, the
step may contain a step of temporarily halting the temperature
increase and retaining the temperature. Further, before reaching a
maximum temperature Tmax in heating, the rate of temperature
increase may be suppressed down to 5 degrees C./min for
instance.
[0031] The maximum temperature Tmax in heating should be selected
to be a proper temperature that is high enough to melt the ternary
or more multicomponent Si alloy according to its composition but is
capable of preventing the reinforcement fibers from deterioration.
Tmax may be determined to be 1395 degrees C. for example, or
properly determined as a value relative to the melting point, such
as the melting point plus 20 degrees C.
[0032] When reaching the melting point, as schematically shown in
FIG. 2B, the ingot 3 starts melting and gradually infiltrating into
the ceramic compact 1 as shown by the reference sign 5. This
process would finish in a relatively short time and, as
schematically shown in FIG. 2C, provides a ceramic matrix composite
10 in which the alloy infiltrates throughout its structure.
[0033] To cause sufficient infiltration, duration of the maximum
temperature is preferably made longer. Extremely long duration,
however, causes deterioration of the reinforcement fibers.
Therefore the duration time should be limited to be properly short.
These factors can be taken into consideration to determine the
duration time.
[0034] The ceramic matrix composite 10, thereafter, is gradually
cooled and then taken out of the furnace (Step S7). To avoid abrupt
thermal shock, any proper cooling rate may be set.
[0035] The obtained ceramic matrix composite would be usually
subject to finishing, thereby providing a final product. Or, still
after finishing, the product may be subject to coating for the
purpose of preventing adhesion of foreign substances or any other
purpose.
[0036] To verify effects by the present embodiment, some tests have
been carried out.
[0037] Some ceramic compacts, which were fabrics of SiC fibers with
SiC powders infiltrating therein by the solid phase infiltration
method respectively, were prepared, and ingots having composites
listed in Table 1 were respectively prepared.
TABLE-US-00001 TABLE 1 Ingots subject to the test Composition (at
%) Test Piece Y Ti other A -- 10 bal. Si B -- 15 bal. Si C 10 --
bal. Si D 18 -- bal. Si E -- -- 9.2 at % Hf-bal. Si F 2 6 bal. Si G
2 10 bal. Si H 2 15 bal. Si I 4 6 bal. Si J 4.3 9.7 bal. Si K 4.8
7.8 bal. Si L 6 4 bal. Si M 6 10 bal. Si N 6 15 bal. Si O 8.8 2.1
bal. Si
[0038] The ingots were respectively combined with the
aforementioned ceramic compacts and heated in a vacuum to cause
melting and infiltration. Its temperature profile conformed with
that described already. Tmax of them aside from the test piece D
were 1395 degrees C. and that of test piece D was 1250 degrees
C.
[0039] The obtained ceramic matrix composites were respectively cut
and polished on the sectional surfaces, and were subject to
sectional observation using a scanning electron microscope
(SEM).
[0040] In the test piece B (Si-15 at % Ti) and the test piece E
(Si-9.2 at % Hf), voids were clearly observed on these sectional
surfaces and more specifically it is clear that infiltration of Si
was insufficient. In the test piece C (Si-10 at % Y), however,
voids were not clearly observed. Further, in the test pieces F
through O (ternary alloys), prominent voids were not observed. More
specifically, it is clear that the Y--Si alloy and the ternary Si
alloys including Y are superior in infiltration ability.
[0041] Using image analysis, voids were discriminated from the
other on the sectional surfaces and these areas were measured.
Infiltration ratios were calculated in regard to the respective
test pieces, where an infiltration ratio is defined as (the total
area-the area of the gaps)/the total area.times.100%. Results are
summarized in FIG. 3.
[0042] The test pieces F through O (ternary Si alloys) and the test
piece C are found to have higher infiltration ratios as compared
with the test pieces B, E (binary Si alloys). It could be
recognized that combined addition depresses melting points as
described earlier and as well improves the infiltration ability. At
least in a condition that Ti is added in combination, 2 at % or
more Y addition is effective for suppressing defects in ceramic
matrix composites.
[0043] Analysis on the sectional surfaces by using EPMA was carried
out. Probe diameters were 30 micrometers .PHI. and measurements on
randomly selected 25 points were respectively carried out.
Compositions on 24 points, as 1 point being excluded, were averaged
respectively and the results are listed in Table 2.
TABLE-US-00002 TABLE 2 Results of composition analysis by EPMA
Composition (at %) Test Piece C Si O Y Ti C 32.17 64.23 0.53 3.07
-- D 32.08 59.08 1.26 7.58 -- F 31.55 64.12 0.26 1.56 2.51 G 30.68
64.60 0.30 0.81 3.80 H 28.78 63.77 0.31 0.91 6.23 I 28.77 66.68
0.50 1.19 2.85 J 30.03 65.08 0.55 1.44 2.90 K 30.82 63.65 0.44 1.20
3.89 L 30.41 66.47 0.26 1.70 1.17 M 30.55 62.36 1.21 2.30 3.58 N
29.65 59.66 1.12 2.96 6.62 O 31.90 64.44 0.62 2.48 0.56
[0044] The respective test pieces were further subject to exposure
tests in which test pieces were exposed to the air at 1100 degrees
C. for 100 hours and thickness reductions by oxidation were
measured. The thickness reductions are divided by the exposure time
to get oxidation ratios, which are summarized in FIG. 4.
[0045] As the Y concentration is put on the horizontal axis, FIG. 4
shows influence of the Y concentration on oxidation resistance. It
is acknowledged that the oxidation rate has a positive slope with
respect to the Y concentration. Specifically, at least in a
condition of combined addition with Ti, addition of Y is
disadvantageous in light of oxidation resistance of ceramic matrix
composites, and in particular 6 at % or less Y addition is
preferable.
[0046] Further, the respective test pieces were machined into
rectangular test pieces having dimensions of 50 (length).times.10
(width).times.2 (thickness) mm, and Young's moduli were
respectively measured on the basis of a resonance method. Results
are shown in FIG. 5.
[0047] As the Ti concentration is put on the horizontal axis, FIG.
5 shows influence of the Ti concentration on Young's moduli. It is
acknowledged that the Young's modulus has a positive slope with
respect to the Ti concentration. Specifically, at least in a
condition of combined addition with Y, addition of Ti is effective
in increase of the Young's modulus. In particular, addition up to 6
at % is prominently positive in the effect of addition but any
greater addition moderates increase of the Young's modulus.
Specifically, addition of 6 at % or more Ti is preferable in light
of increase of the Young's modulus, and 10 at % or less addition is
preferable if saturation of the effect is considered.
[0048] Although certain embodiments have been described above,
modifications and variations of the embodiments described above
will occur to those skilled in the art, in light of the above
teachings.
INDUSTRIAL APPLICABILITY
[0049] A production method of ceramic matrix composites is
provided, which prevents deterioration of reinforcement fibers at
high temperatures in a step of melting.
* * * * *